This presentation is based on a report prepared for Kodak and submitted
to the Assassinations Records Review Board. The Kodak report is now in the
possession of the National Archives who are responsible for its control and
distribution. Permission was granted for me to make this technical presentation
on the image capture characteristics of the Bell & Howell Model 414PD 8mm
roll film camera to the MMS. The Model 414PD camera was used by Abraham
Zapruder to film the assassination of President John F. Kennedy. It is the
intention of the National Archives to make the full report public in the near
future - possibly including distribution on the World Wide Web. This handout
therefore provides only a brief synopsis and outline. -Roland J. Zavada, 10/24/98

Objective: This study resulted from a request of the Assassinations
Records Review Board to Kodak, to conduct film tests using a Model 414 PD
Bell & Howell Zoomatic Director Series camera to determine whether the
recognized anomalies in the Zapruder film held by the National Archives are
borne out by actual tests.

Introduction

Just after noon on November 22, 1963,
Mr. Abraham Zapruder, a woman's clothing manufacturer, climbed onto a small
concrete pedestal in Dealey Plaza with his 8mm movie camera. After President
Kennedy's motorcade came into view and passed, Mr. Zapruder's 26 second film
record of the assassination became the most significant amateur recording of a
news event in history.

The Bell & Howell 414PD 8mm camera was, in 1963, a top of the line, high
quality 8mm amateur movie camera. The optics were outstanding, the drive
mechanism provided consistent long-run exposure time/per wind, the automatic
exposure mechanism was of award winning design that yielded excellent results
and the camera had a power zoom lens. The "P" in the model reference stood for
"Power Zoom" and the "D" for "Dual Electric-Eye." The image formed within the
standardized projectable area had no flaws or faults. Why then have we made
an extensive study of the camera's image capture characteristics?

The camera used is not untypical of several models that position the film
with its claw moving in an aperture cutout area adjacent to the image forming
picture area. Consequently, scene information falls into this unmasked area
due to the excess (circular) imaging area produced by the lens. For normal
home movie projection this additional recorded scene information would be of
no consequence as the projector aperture would hold back or mask-out this
area.

We have the typical camera aperture area (i.e. the images that would be viewed
by standard projection), and an additional area where the image extends into the
area between the perforations and adds to the total scene content. To some
students of the assassination, the Zapruder original film contains several
image anomalies - almost all being related to the scene information recorded or
imaged into the area between the perforations. (See sample frames below shot in
Dealey Plaza.)

There is great significance attached to this area by various researchers who
speculate that the anomalies may represent not the peculiar optics of Zapruder's
Bell & Howell camera but rather, evidence of film alteration. It is important,
therefore, to understand how the camera optics record images in this area and
why certain anomalies are present - which is part of the objective of this study.

Overview of Image Anomalies:

The image characteristics that have been identified as "those of concern" are
inconsistencies; i.e. they are not the same density, color and quality as those
contained in the primary image area. The cause of those inconsistencies thus
provides a focus for our review of camera characteristics. A look at a few
frames from the Zapruder "in camera" original, provide a "picture" of the
image characteristic that will be the bases of detailed discussions.
(See Photo from the Warren Commission Exhibit.)

Image anomalies or characteristics that were addressed are:

Claw Shadow -Between the perforations there is a broad bar where
the image has more density (darker) than the primary image area.

Claw or aperture Flare - Sometimes adjacent to the dark (claw
shadow) bar and between it and the primary image is a "streak" lighter than the dark bar and the adjacent image.

Ghost Images - Sometimes there appears to be "ghost"
images such as a motorcycle fender. These are real images, which because of
the design of the claw cutout area occur simultaneously above and below the
perforation holes of the primary image being formed.

First Frame Overexposure - Occurs in the Zapruder original with his
first exposure of the motorcade and at least twice in his filming of the first half
of the roll. The possible causes of the fogged or lesser density first frame are
reviewed, to the best extent possible - recognizing the limitation that we could
not conduct a practical test with the Zapruder B&H 414 PD camera.

The camera mechanism includes a negator spring motor drive which, when
released by a pivotal movement of a control
arm from its position (by pushing down on the start button),
serves to rotate a scroll gear to drive a worm (gear). This worm serves
to rotate a film footage indicator dial, and to rotate a gear carrying a crank
pin to oscillate a shuttle or film pulldown claw and rotate a shutter,
as well as drive a governor, and to rotate gears. The shuttle is
urged by spring (pressed against the film) toward feeding
engagement with the film (i.e., to engage the perforation holes) in a
position between an aperture plate incorporating an exposure aperture (area)
and a pressure plate (to hold the film flat and motionless during exposure).
The shuttle is pivoted on a pin. The gear also carries a known disc
segment type of shutter which covers the aperture during frame-by-frame
feed of the film and when the camera is stopped.

Film Intermittent:

In the ratchet type, the claw is normally brought into contact with the film
by the action of a light spring. The claw can reciprocate (out of one perforation
into the next) in a single plane because its upper edge is tapered so that it will
ratchet or cam out of engagement with a perforation at the beginning of the
upward movement. The claw will ride along the surface of the film through its
entire upward or return stroke until it drops into the succeeding perforation hole.
This type of mechanism is the simplest form of the two mentioned, and is the type
employed in the Bell & Howell 414PD Camera. (See Drawing)

Camera Aperture:

The drawing shown provides the representative dimensions of the aperture,
which limits image height, inside edge and shows the cutout for the intermittent
claw. The characteristics of the aperture cutout are directly related to our study
of image anomalies, note the size and location of the cutout for the pulldown
claw adjacent to the Standardized (0. 192 in. nom. width) image area. Note that
the height of the opening for the claw movement is necessarily greater (0.263 in.)
than the perforation pitch (0. 150 inch) plus one perforation height (0.050 inch).
The significance of the size of this opening will be emphasized when we
discuss Multiple Exposure Areas.

Shutter/Exposure Time:

The shutter, for the great majority of motion picture cameras, employs a rotating
disc with an open sector to allow light from the lens to reach the film during its
stationary exposure period. During the period when the opaque sector of the
shutter obscures the light from the lens, the next frame of the film is moved and
relocated by the intermittent. The Bell & Howell 414PD camera uses a
shutter having an open sector the equivalent of about 165' to 170' resulting in
an exposure time of 0.025 second (or 1/40th of a second) per frame.

Motor/Governor:

Early spring wound movie cameras were limited by their clock-spring wind-up
motors which were a challenge to designers to maintain constant torque to
transport the film at a uniform velocity because of inertial (acceleration) effects
from the start of the clutched spring motor. Their run time was relatively short.
In the late 50's and early 60's a major change occurred for the high-end cameras
with the introduction of the negator spring. The B&H 414 Camera series
was the first of the Bell & Howell line to incorporate the negator spring.
The negator spring motor provided an almost constant torque throughout its
effective run time and essentially "negated" transport speed effects. Further,
the run time was extended significantly. The differences in run time were in
the order of double, from 25 - 30 seconds to more than a minute (15 feet of
film).

Film Velocity/Frame Rate:

The question of frame rate of the Zapruder
camera was an important technical consideration of the FBI in their investigation
of the timing of the three shots. The FBI reported that their studies showed the
camera to be operating at 18.3 fps, or 2.3 fps fast according to the (then) published
standard and the reference in the owner's manual.

Evolution of Standards to Higher Frame Rates: It has been
acknowledged that Bell & Howell's and Eastman Kodak's engineering
practice for cameras moved toward 18 fps in the late 50s, and that this velocity
was not uncommon in USA practice. The committee action to change standards
takes time. The published standard for camera velocity in use in 1963 issued
in 1954. Standards reflect practice and the evolutionary change to the
higher frame rate of 18 frames per second was subsequently recognized in
American National Standards that issued in October of 1964 , for
Camera and Projector Usage - PH22. 21 and PH22.22. Bell & Howell testing
confirmed that the Zapruder camera operated at slightly faster than 18fps -
meeting the requirements of the revised standard.

Optical/Image Characteristics

Varamat Zoom Lens:

The 3: 1 zoom lens of the 414 camera
series had eleven elements and reported to be of excellent quality. That quality
position was confirmed in correspondence from the former Director of
Engineering of the Optical Division, Mr. Rudolf Hartmann. He related: "the
Varamat had an unusually flat resolution curve across its picture format (9
field position, 3 focal lengths, full aperture), yielding more than 60 lp/mm
(line pairs per millimeter) resolution. Visual (air-image) resolution was 225 I/mm
min. at any test position."

Any attempt on my part to provide details on the lens or the zoom mechanism
would be redundant. Dr. Cox and Mr. Mellberg confirmed that their patents,
Cox #3074317 and Mellberg #3059533, are directly applicable to the 414 camera
series.

"Windows" of the Lens:

In simplest terms the entrance window of a lens defines the area of the
object we are looking at; and the image in the lenses following it is called the
exit window, since this defines the area of the image seen. To determine
if the exit window size varied, the aperture plate was removed and a light
was imaged through the lens onto frosted acetate to observe (as close as
possible to the film plane) any change in exit window size with changes in
focal length. We observed that there were changes. Although the full exit
window remained almost the same, the effective illumination area changed
by the presence of dark peripheral rings at the wide angle through normal lens
setting. These dark rings began at a diameter slightly greater than the image
area diagonal. (See drawing and
photos on cover page.)

Electric Eye and Iris Diaphragm:

An article, A Direct Drive Automatic Iris Control, by LaRue, Bagby, Bushman,
Feeland and MacMillin was published in the September 1958 issue of the SMPTE
Journal and gives the reader design and engineering details on the automatic
exposure system. The exposure sensing is achieved by feedback from two
photo-voltaic (Se) cells, one sensing overall scene illumination and the other
sensing paraxial luminance for backlight compensation. (Hence the "D" in
414PD relates to dual electric eye.)

The iris diaphragm in the 414 camera series uses two overlapping disks
each of which has a wedge shaped angular slot. The intersection of the two
slots forms the variable aperture. Gear teeth are formed on the periphery of
the disks that engage a gear mounted on the meter coil.
(See drawing below.)

Unusual Iris Shapes:

Because the cut of slots in the two iris blades are not linear (as shown), unusual
patterns can be formed as seen from the series of photographs of aperture
openings. The subject of iris patterns and its effect on the resulting image is
well documented in the literature on optical physics. Its significance here is the
question of whether or not the possible unusual patterns yielded image
artifacts. If the subject is not in focus inversion, multiple images, etc.
can and do occur. However, if the image is focused properly, the iris pattern
makes no difference. The question presents itself - are Mr. Zapruder's images
in focus? By examination they appear to be. Did an unusual iris pattern
contribute to any of the artifacts seen? In my opinion, I doubt it.

Recognized Image
Anomalies in the Zapruder Original Film

Image Penetration
between the Perforations:

The characteristics and depth of the image penetration are not always seen the
same but do follow a consistent and repeatable pattern. The pattern is directly
related to the effective image area from the exit window of the Varamat
lens, the focal length of lens and in some cases, the aperture setting. We can
show and conclude that:
The telephoto lens setting consistently produces the maximum image
penetration into the perforation area;

Normal lens focal length produces some but not full penetration into
the perforation area; and

One of the image anomalies seen is a darker (higher density) band or wide bar
in the image area between the perforations. This anomaly can be noted in the
Zapruder frames as well as my practical test, photos. This higher density (band
or streak) can be explained as being caused by the shadow of the intermittent
claw (and its supporting arm) as it moves upward over the film to engage the
following perforation and pull down the next frame. The pull-down is with the
shutter closed, but the upward movement of the claw out of the perforation,
over the area between the perforations, into the next perforation hole is done
while the shutter is open and the film is being exposed. The claw movement
over the area between the perforations reduces the amount of light reaching
the film causing more density. (Less light is more density on a reversal film.)
The reduction in exposure to the area behind the claw is not linear. The claw
functions with a shutter crank pin engaging the claw slot giving a sinusoidal
time relationship to the pulldown ratchet reentry action.

Claw or Aperture Flare:

Claw flare appears to be a very real image
anomaly often, but not always, seen adjacent to the dark bar caused by the claw
shadow and the normal image area. In addition, when the 8mm image is viewed
normal, the bottom of the upper perforation may show some flare-like density
difference. It is this perforation that "sees" the bottom of the claw arm as it
enters the perforation hole and pauses before beginning its rapid positioning
stroke.
(See also cover photo.)

Multiple Exposure Areas -
Perforation-Like Images

Within the perforation area, adjacent to
a perforation above or below or both, an image occurs that resembles a
perforation. The images simply represent multiple, i.e. double exposure of
the area of the "excess" aperture cutout for the intermittent claw action.
Above the upper and below the lower perforation hole, the excess aperture
cutout allows an image to be formed concurrent with the primary image.
When the succeeding image is formed it adds light to that previously formed
causing multiple or double exposure. The shape that this image area takes,
and importantly whether it exists at all, is directly dependent on the size of
the exit window of the lens based on the chosen focal length together
with the influence of scene content. Not all exposure conditions produce the
phenomena, however telephoto in bright lighting conditions does. With blank
frames between some test target exposures, the phenomenon is visible and
multiple exposures adjacent to the perforations are easily seen.
(See photo below.)

Ghost Images:

In the Zapruder motorcade scene, below
the perforation, you were shown a white object heading toward a bystander in
the primary image. This so-called ghost image has caused a lot of speculation and
questions from many that examined the Zapruder film. Now, by our understanding
of the multiple exposure around the perforations explained above, it is reasonable
to conclude the cause as simple double exposure of a primary image super
imposed on the excess image of the preceding frame.
(See ghosting on test chart below.)

First Frame Over-Exposure:

The first frame of advance motorcade
scene shows an over exposure condition, known as "first-frame-overexposure." In
my discussions with M.E. Brown, former Manager of the 16mm and 8mm
Department at Eastman Kodak, the condition was undesirable and a
development/design problem to be avoided, but a not uncommon occurrence.

Mr. Zapruder's camera appears to have been prone to the problem. The
Secret Service copies of his family pictures show two other occurrences of first
frame over exposure. With my test cameras, I had one, #3, that consistently had
a noticeable first frame over exposure by about one-third of a stop. We were not
given the opportunity to run a practical test with Zapruder's camera to determine
if the first frame artifact was a consistent problem or unique to the assassination
film roll.

Conclusion

It is my conclusion that all the
inter-perforation image anomalies identified can be explained by the design
and image capture characteristics of the Bell & Howell 414PD Camera.